1. Field of the Invention
The present invention relates to a memory access control system. More particularly, it relates to an access control system for a main memory having a plurality of memory banks. The present invention is advantageously used in the main memory of a computer system.
2. Description of the Related Art
Recently, a method was disclosed for dividing the main memory of a computer system into a plurality of memory banks, thus enabling parallel processing for the data and raising the practical throughput for the data in the main memory.
In this method, at least two data bus lines are provided for inputting write data and for outputting read data. Each of the data bus lines is used separately for input and output operations to facilitate control of the bus line and to raise the throughput for the data.
In this case, however, there is a fifty percent limitation value on the utilization efficiency of the bus line, because either the input or the output bus line is selected alternatively for every request for access to the memory. The problems concerning the utilization efficiency of the bus lines will be explained in detail hereinafter.